Carburetor emission control device

ABSTRACT

The throttle valve of a carburetor is limited in its closing movement by a mechanically and electrically controlled stop, a solenoid connected to the engine ignition circuit is energized upon engine start up to limit closing movement of the throttle valve to a normal idle speed position, engine shutdown permitting closing of the throttle valve by deenergization of the solenoid, subsequent depression of the vehicle accelerator pedal opening the throttle valve and positioning an additional stop means to prevent closing of the throttle valve beyond a fast idle position, for starting purposes.

UIIItQd States atent n91 Dickensheets et a1.

[ 1 .iune 5, 1973 [54] CARBURETOR EMISSION CONTROL DEVICE [75]lnventors: William E. Dickensheets, Southfield; Alvin P. Nowroski,Livonia, both of Mich.

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

[22] Filed: Nov. 29, 1971 [21] Appl. No.: 202,894

[52] U.S. Cl ..l23/l98 DC, 123/DIG. ll [51] Int. Cl.. ....F02m 3/02,F021) 77/08, F02d 11/08 [58] Field of Search ..l23/DIG. 11,97 B, 123/198D, 198 DB, 198 DC, 179 B6, 179

[56] References Cited UNITED STATES PATENTS 2,817,325 12/1957 Meissnerl23/l98DC 3,354,877 11/1967 Zubetal. ..l23/DIG.11

3,398,731 8/1968 Johansson ..123/D1G. 11 3,482,562 12/1969 Runft..123/l98 DC 3,491,737 l/1970 Burnia ..l23/198 DC X 3,618,582 11/1971Gerlitz ..123/198 DB 3,682,148 8/1972 Harrison et a1 ..l23/l98 DB XPrimary ExaminerAl Lawrence Smith Att0rney-Keith L. Zerschling andRobert E.

McCollum [5 7] ABSTRACT The throttle valve of a carburetor is limited inits closing movement by a mechanically and electrically controlled stop,a solenoid connected to the engine ignition circuit is energized uponengine start up to limit closing movement of the throttle valve to anormal idle speed position, engine shutdown permitting closing of thethrottle valve by deenergization of the solenoid, subsequent depressionof the vehicle accelerator pedal opening the throttle valve andpositioning an additional stop means to prevent closing of the throttlevalve beyond a fast idle position, for starting purposes.

12 Claims, 1 Drawing Figure CARBURETOR EMISSION CONTROL DEVICE Thisinvention relates, in general, to means for controlling the movement ofthe throttle valve of a carburetor. More particularly, it relates to amechanically and electrically controlled power means to control fuel andair flow through a carburetor to prevent engine dieseling and minimizethe passage of unburned hydrocarbons into the atmosphere.

The problem of engine dieseling after the engine has been shut off isrecognized. So long as the engine crankshaft continues to rotate, avacuum signal will be present in the carburetor throttle bore below thethrottle valve to pull idle system fuel and air into the hot combustionchamber so that combustion is maintained for a few seconds or longerafter the engine ignition is shut off. This naturally is undesirable.

This invention provides a carburetor throttle valve construction that(1) permits closing of the throttle valve upon engine shutdown to reducefuel and air flow; or (2) is positioned to a curb idle position fornormally maintaining the engine at a normal idling speed; or (3) ispositioned to a faster idle position for the leaner start of a hotengine.

In the prior art devices, the minimum flow and engine idle speedpositions of the throttle valve usually are the same. Therefore, whenthe engine is shut off, the above conditions exist; that is, the vacuumsignal still present for a few seconds draws a sufficient charge offuel/air mixture into the combustion chamber to maintain the enginerunning.

The invention provides a construction in which the throttle valve ismoved to a closed position upon engine shutdown, to reduce flow to thecylinders and prevent dieseling; is moved to a fast idle position forrestarting; and to an engine idle speed position during normal engineoperation so that idle system fuel and air flow can be obtained in theconventional manner.

It is one of the objects of the invention, therefore, to provide acarburetor with a throttle valve positioner that will prevent enginedieseling and minimize the passage of unburned hydrocarbons into theexhaust system or atmosphere, and will reposition the throttle valve fora fast idle restart subsequent to engine shutdown.

It is also an object of the invention to provide the throttle valve of acarburetor with a movement that is controlled mechanically and by asolenoid controlled stop to at times permit closing of the throttlevalve to reduce flow of fuel and air to the engine cylinders, while atother times positioning the throttle valve to a beyond idle position fora better engine start.

It is a still further object of the invention to provide a carburetorwith a multi-position throttle valve actuator mechanically and solenoidcontrolled, the solenoid being controlled by an electrical circuitincluding the engine ignition key.

Other objects, features and advantages of the invention will become moreapparent upon reference to the succeeding detailed description thereof,and to the drawing illustrating a preferred embodiment thereof; wherein;

the FIGURE illustrates schematically a crosssectional view of a portionof a carburetor embodying the invention. v

The FIGURE illustrates a portion of a downdraft type carburetor,although it will be clear as the description proceeds that the inventionis equally applicable to other types of carburetors, such as updraft orsidedraft, for example. More particularly, the carburetor is providedwith a main body portion 12 having a cylindrical bore 14 containing aconventional venturi (not shown) in an air/fuel induction passage 16.The latter is open at its upper end to air at essentially atmosphericpressure passing through the conventional air cleaner, not shown. At itslower end 20, passage 16 is adapted to be connected to an engine intakemanifold, from which the air and fuel mixture passes to the enginecylinders, not shown, in a known manner.

The flow of air and fuel through induction passage 16 is controlled inthis instance by a conventional throttle valve 22. The latter is fixedlymounted on a shaft 24 rotatably mounted in the side walls of body 12, ina known manner. A main fuel system is not shown, since it can be any ofmany known types. The fuel would be inducted into passage 16 above thethrottle valve in a known manner as a function of the rotation of thethrottle valve from its fully closed position 34 to its wide open nearlyvertical position, by the change in vacuum signal.

The carburetor also contains an idle system for supplying the necessaryfuel and air to the engine cylinders during engine idling speedoperation. A bypass passage 26 contains the usual transfer port 28 and adischarge port 30 controlled by an adjustable needle valve 32.

The transfer port 28 is located in this case so that its lower edge isaligned with the edge of the throttle valve plate in its closed position34. Alternatively, if desired, the transfer port can be locatedvertically in other positions relative to the throttle plate edge whenin the closed position.

The dotted line position 36 indicates the idle speed position of thethrottle valve, while position 37 indicates a fast idle speed or enginehot start position, to be described more fully later.

It will be clear that in the closed position 34, the idle passage areaexposed to the vacuum existing below the throttle valve is reduced fromthat when the throttle valve is in position 36. Therefore, a lowerquantity of fuel and air will flow at this time as the area of thetransfer port 28 above the throttle valve edge subjects passage 26 to anambient or atmospheric pressure bleed. The quantity flowable past theneedle valve at this time, therefore, is determined to be insufficientto provide the torque necessary to overcome the engine friction.

It will also be seen that when the throttle valve is positioned in itsidle speed dotted line position 36, the transfer port area subjected tothe vacuum signal below the throttle valve is increased so as toincrease the amount of fuel and air to pass through the idle system tothe amount needed to maintain the engine at the desired idling speed. Itwill also be clear that when the throttle valve is moved to position 37,a leaner start of a hot engine will occur. More fuel vapor exists with ahot engine. Therefore, a greater throttle valve opening provides moreair flow to produce the desired starting air/fuel ratio.

To accomplish the above, a lever or link 38 is fixed on or formedintegral with throttle valve shaft 24 for rotation with it, a tensionspring 40 biasing lever 38 in a counterclockwise direction at all timesto bias the throttle valve towards its closed position 34.

Lever 38 is adapted to be positioned clockwise to the right, as seen inthe FIGURE, to locate the throttle valve clockwise to its normal idlespeed position 36, or to the fast engine idle speed position 37, by asolenoid controlled stop 42. The latter includes a solenoid 43 that isadjustably mounted in a bracket 44 secured to the carburetor housing 46,and has an armature 48 movable between the full line position 50 shownand the dotted line position 52, as a function of the operativeness orinoperativeness of the engine.

That is, the operation of the solenoid 43 is adapted to be tied in withthe engine ignition system shown schematically as including a line 54connecting the solenoid through the engine on-off ignition switch 56 tothe battery 58 having a ground connection as indicated. Thus, when theignition key is turned on, for example, an electrical circuit iscompleted to solenoid 43 to energize the same and move armature 48 tothe dotted line position 52. When the ignition system is shut off, forengine shutdown, deenergizatiori of solenoid 43 causes armature 48 to beretracted by a conventional spring, not shown, to the full line position50 shown.

In this case, the dotted line position 52 of solenoid armature 48 stopsthe leftward movement of lever 38 at a point corresponding to thedesired normal idle speed position 36 of throttle valve 22. The fullline position 50 permits the lever 38 to move leftwardly to the fullyclosed position 34 of the throttle valve.

An additional linkage 60 is provided cooperating with the solenoidarmature to control the position of the lever 38 for fast idle startposition 37, as well as the normal idle speed position 36. Morespecifically, linkage 60 includes a finger-like lever 62 hinged to thesolenoid case for a pivotal arcuate movement. The lever is bent near itscentral portion to form a bead-like abutment or cam surface 64 restableby gravity on the armature 50. A conical cam 51 fixed on armature 48 isadapted to engage and cam the lever 62 upwardly to the dotted lineposition 66 as the armature 48 moves from the full line to the dottedline position upon energization of the solenoid.

The end 68 of lever 62 is adapted, when the armature 48 is retracted asshown, to constitute a stop by engaging lever 38 and preventing furthercounterclockwise movement than shown. This prevents the throttle valve22 from closing more than to the fast idle position 37. Verticalswinging movement of lever 62, when armature 48 moves rightwardly, liftsthe finger end 68 out of contact with lever 38 and permits the lever toreturn the throttle valve 22 either to the normal idle speed position36, or to the closed throttle speed position 34, when armature 48 isretracted.

To summarize briefly before proceeding to the operation, the purpose ofthe throttle positioner is to provide three positions for emissioncontrol; namely, a starting position, in which the throttle valve isopened beyond idle position to provide a leaner start of a hot engineand yet a good start of a colder engine; secondly, a curb idle positionagainst a solenoid armature to which the throttle valve is returnedafter start and during deceleration operation; and, thirdly, an engineanti-dieseling position in which the solenoid armature is retracted uponengine shutoff to permit full closure of the throttle valve, with asubsequent return to the engine start, fast idle position after arepositioning of the throttle valve by the vehicle operator.

In operation, the parts are shown in the engine-off condition positionedfor a fast idle start operation. Prior to the start of the engine, thevehicle operator would depress the accelerator pedal. This will rotatethe throttle valve 22 open to or beyond the position 37. With the engineoff, solenoid 43 will be deenergized by the open ignition switch 56breaking the circuit to battery 58. Accordingly, armature 48 will beretracted to the full line position 50 shown, retracting cam 51leftwardly and permitting lever 62 to drop down onto the armature 48.This positions the finger stop 68 in the path of return movement oflever 38 towards a closed throttle position. Release of the acceleratorpedal by the operator, therefore, will permit spring 40 to positionlever 38 against stop 68 and position throttle valve 22 in the fast idlespeed position 37.

As soon as the engine is cranked, the solenoid armature 48 is moved tothe right to the curb idle position indicated at 52. This cams thefinger lever 60 upwardly to the dotted line position 66, and permits thethrottle return spring 40 now to move lever 38 and the throttle valve tothe normal idle speed setting 36. Subsequent depression of theaccelerator pedal and release will again return the throttle valve leveragainst the end of armature 48 to the curb idle speed position 36.

Assuming now the engine is shut off, the solenoid armature 48immediately will retract to the anti-dieseling position 50. Since thelever 38 is already to the left and under the end 68 of finger lever 62,the lever 38 now can move leftwardly with the solenoid armature toposition the throttle valve 22 in the closed throttle setting 34. Thisreduces the fuel and air flow throughthe idle system below the levelnecessary to sustain, running of the engine, and, therefore preventsdieseling.

We claim:

1. An engine anti-dieseling control comprising, in combination, anengine carburetor having an induction passage open to atmosphericpressure at one end and adapted to be connected to an engine intakemanifold at the opposite end so as to be subject to engine vacuumvarying in level from ambient atmospheric pres sure at engine shutdownto a maximum subatmospheric pressure level during engine decelerationoperating conditions, a throttle valve rotatably mounted across thepassage and movable from a closed position to an engine idle speedposition and beyond to a wide open throttle position, and return, forcontrolling flow through the passage, an idle fuel/air mixture channelconnected to the induction passage below the closed position of thethrottle valve so that the idle channel is subjected to manifold vacuumat all times to provide normal idle and beyond normal idle speed mixtureflow, and control means to move the throttle valve to and between thepositions, the control means comprising a lever fixed to the throttlevalve, adjustable stop means operably positionable in the path ofmovement of the throttle valve in a closing direction to determine thedegree of closing of the throttle valve as a function of the operationand inoperation of the engine, the stop means comprising a first membermovable to a first stop position in response to engine startup to limitclosing movement of the throttle valve to an idle speed position, thefirst member being movable to a second position in response to engineshutdown permitting movement of the throttle valve to a closed throttleposition to prevent engine dieseling, and second means movable at timesin response to movement of the first member and movable between firstand second positions into and out of, respectively, the path of closingmovement of the throttle valve lever, movement of the second means toits first position limiting closing movement of the throttle valve to afast idle speed position more open than the first aforementioned idlespeed position, for engine starting purposes.

2. An engine control as in claim 1, the first member comprisingelectrically actuated means connected to the engine ignition circuit soas to be responsive to engine operation and inoperation for moving thefirst member between its second and first positions respectively.

3. An engine control as in claim 1, the first member comprising asolenoid connected to the engine ignition circuit and having an armaturemovable from the first to second positions as a function of theoperativeness or inoperativeness respectively of the engine to eitherlocate the throttle valve at an idle speed position or at a closedthrottle position.

4. An engine control as in claim 1, the second means comprising latchmeans engagable by the first member in response to the movement of thefirst member from its second to its first position to move the latchmeans to its second position out of the path of closing movement of thethrottle valve lever to thereby permit movement of the throttle valvelever to the idle speed position.

5. An engine control as in claim 4, the movement of the throttle valvelever to the idle speed position rendering the latch means inoperativeand permitting further movement of the throttle valve to a closedposition in response to engine shutdown moving the first member to itssecond position.

6. An engine control as in claim 4, the latch means comprising apivotally mounted finger-like member located in its first positionadjacent the first member, and cam means on the first member engagablewith the finger-like member to cam it away from the path of closingmovement of the throttle valve lever.

7. An engine control as in claim 4, the first member comprising asolenoid moved member connected to the engine ignition circuit so as tobe responsive to engine operativeness and inoperativeness to energize ordeenergize the solenoid to move the member between its positions, thesolenoid moved member having cam means thereon engagable with the latchmeans.

8. An engine control as in claim 5, the movement of the throttle valvelever to the idle speed position rendering the latch means inoperativeand permitting further movement of the throttle valve to a closedposition in response to engine shutdown moving the first member to itssecond position.

9. An engine anti-dieseling control comprising, in combination, anengine carburetor having an induction passage open to atmosphericpressure at one end and adapted to be connected to an engine intakemanifold at the opposite end so as to be subject to engine vacuumvarying in level from ambient atmospheric pressure at engine shutdown toa maximum subatmospheric pressure level during engine decelerationoperating conditions, a throttle valve rotatably mounted across thepassage and movable from a closed position to an engine idle speedposition and beyond to a wide open throttle position, and return, forcontrolling flow through the passage, an idle fuel/air mixture channelconnected to the induction passage below the closed position of thethrottle valve so that the idle channel is subjected to manifold vacuumat all times to provide normal idle and beyond normal idle speed mixtureflow, the control means comprising a lever fixed for rotation with thethrottle valve, a solenoid connected to the engine ignition circuit soas to be responsive to engine operativeness and inoperativeness to beenergized or deenergized respectively, the solenoid having an armatureprojecting into the path of movement of the throttle valve lever in athrottle valve closing direction to stop the latter movement, thearmature having a first deenergized position permitting the throttlevalve to close to prevent engine dieseling upon engine shutdown, and asecond energized position stopping the movement of the throttle valve atan engine idle speed position, other stop means movable into and out ofthe path of the throttle valve lever, the other stop means when engagedby the lever preventing closing movement of the throttle valve beyond afast idle speed position more open than the first mentioned idle speedposition, for engine starts, the armature having a cam thereon engagablewith the other stop means upon movement of the armature to its energizedposition to cam the other stop means out of engagability with thethrottle valve lever to permit closing movement of the lever to the idlespeed and closed throttle position.

10. An engine control as in claim 9, the other stop means being hingedlymounted on the solenoid, and movable by its own weight to abut thearmature and in the path of movement of the throttle valve lever.

11. An engine control as in claim 10, the throttle valve lever whenmoved to the idle speed position blocking return movement of the otherstop means to a position in the path of movement of the throttle valvelever, thereby permitting movement of the throttle valve lever to aclosed throttle position in response to deenergization of the solenoid.

12. An engine control as in claim 11, the other stop means moving intothe path of movement of the throttle valve lever subsequent to engineshutdown in response to movement of the throttle valve lever to the fastidle speed position or beyond to a more open throttle valve position, tocondition the throttle valve for an engine start setting upon subsequentrelease of the throttle valve in the closed throttle valve direction.

1. An engine anti-dieseling control comprising, in combination, anengine carburetor having an induction passage open to atmosphericpressure at one end and adapted to be connected to an engine intakemanifold at the opposite end so as to be subject to engine vacuumvarying in level from ambient atmospheric pressure at engine shutdown toa maximum subatmospheric pressure level during engine decelerationoperating conditions, a throttle valve rotatably mounted across thepassage and movable from a closed position to an engine idle speedposition and beyond to a wide open throttle position, and return, forcontrolling flow through the passage, an idle fuel/air mixture channelconnected to the induction passage below the closed position of thethrottle valve so that the idle channel is subjected to manifold vacuumat all times to provide normal idle and beyond normal idle speed mixtureflow, and control means to move the throttle valve to and between thepositions, the control means comprising a lever fixed to the throttlevalve, adjustable stop means operably positionable in the path ofmovement of the throttle valve in a closing direction to determine thedegree of closing of the throttle valve as a function of the operationand inoperation of the engine, the stop means comprising a first membermovable to a first stop position in response to engine startup to limitclosing movement of the throttle valve to an idle speed position, thefirst member being movable to a second position in response to engineshutdown permitting movement of the throttle valve to a closed throttleposition to prevent engine dieseling, and second means movable at timesin response to movement of the first member and movable between firstand second positions into and out of, respectively, the path of closingmovement of the throttle valve lever, movement of the second means toits first position limiting closing movement of the throttle valve to afast idle speed position more open than the first aforementioned idlespeed position, for engine starting purposes.
 2. An engine control as inclaim 1, the first member comprising electrically actuated meansconnected to the engine ignition circuit so as to be responsive toengine operation and inoperation for moving the first member between itssecond and first positions respectively.
 3. An engine control as inclaim 1, the first member comprising a solenoid connected to the engineignition circuit and having an armature movable from the first to secondpositions as a function of the operativeness or inoperativenessrespectively of the engine to either locate the throttle valve at anidle speed position or at a closed throttle position.
 4. An enginecontrol as in claim 1, the second means comprising latch means engagableby the first member in response to the movement of the first member fromits second to its first position to move the latch means to its secondposition out of the path of closing movement of the throttle valve leverto thereby permit movement of the throttle valve lever to the idle speedposition.
 5. An engine control as in claim 4, the movement of thethrottle valve lever to the idle speed position rendering the latchmeans inoperative and permitting further movement of the throttle valveto a closed position in response to engine shutdown moving the firstmember to its second position.
 6. An engine control as in claim 4, thelatch means comprising a pivotally mounted finger-like member located inits first position adjacent the first member, and cam means on the firstmember engagable with the finger-like member to cam it away from thepath of closing movement of the throttle valve lever.
 7. An enginecontrol as in claim 4, the first member comprising a solenoid movedmember connected to the engine ignition circuit so as to be responsiveto engine operativeness and inoperativeness to energize or deenergizethe solenoid to move the member between its positions, the solenoidmoved member having cam means thereon engagable with the latch means. 8.An engine control as in claim 5, the movement of the throttle valvelever to the idle speed position rendering the latch means inoperativeand permitting further movement of the throttle valve to a closedposition in response to engine shutdown moving the first member to itssecond position.
 9. An engine anti-dieseling control comprising, incombination, an engine carburetor having an induction passage open toatmospheric pressure at one end and adapted to be connected to an engineintake manifold at the opposite end so as to be subject to engine vacuumvarying in level from ambient atmospheric pressure at engine shutdown toa maximum subatmospheric pressure level during engine decelerationoperating conditions, a throttle valve rotatably mounted across thepassage and movable from a closed position to an engine idle speedposition and beyond to a wide open throttle position, and return, forcontrolling flow through the passage, an idle fuel/air mixture channelconnected to the induction passage below the closed position of thethrottle valve so that the idle channel is subjected to manifold vacuumat all times to provide normal idle and beyond normal idle speed mixtureflow, the control means comprising a lever fixed for rotation with thethrottle valve, a solenoid connected to the engine ignition circuit soas to be responsive to engine operativeness and inoperativeness to beenergized or deenergized respectively, the solenoid having an armatureprojecting into the path of movement of the throttle valve lever in athrottle valve closing direction to stop the latter movement, thearmature having a first deenergized position permitting the throttlevalve to close to prevent engine dieseling upon engine shutdown, and asecond energized position stopping the movement of the throttle valve atan engine idle speed position, other stop means movable into and out ofthe path of the throttle valve lever, the other stop means when engagedby the lever preventing closing movement of the throttle valve beyond afast idle speed position more open than the first mentioned idle speedposition, for engine starts, the armature having a cam thereon engagablewith the other stop means upon movement of the armature to its energizedposition to cam the other stop means out of engagability with thethrottle valve lever to permit closing movement of the lever to the idlespeed and closed throttle position.
 10. An engine control as in claim 9,the other stop means being hingedly mounted on the solenoid, and movableby its own Weight to abut the armature and in the path of movement ofthe throttle valve lever.
 11. An engine control as in claim 10, thethrottle valve lever when moved to the idle speed position blockingreturn movement of the other stop means to a position in the path ofmovement of the throttle valve lever, thereby permitting movement of thethrottle valve lever to a closed throttle position in response todeenergization of the solenoid.
 12. An engine control as in claim 11,the other stop means moving into the path of movement of the throttlevalve lever subsequent to engine shutdown in response to movement of thethrottle valve lever to the fast idle speed position or beyond to a moreopen throttle valve position, to condition the throttle valve for anengine start setting upon subsequent release of the throttle valve inthe closed throttle valve direction.